Device and methodology for early detection of fluid loss and notification and system shutdown for a closed loop fluid heat transfer system

ABSTRACT

A hydronic system and method of use that will maintain normal system operating pressure while also reliably detecting even very small fluid losses in any closed loop fluid heat transfer system is described. The system includes a controller having clock or timing functionality in communication with one or more pressure sensors and a fluid supply valve that provides one or more notifications when the pressure drops below predetermined levels during predetermined periods of time. Depending on the nature of the pressure loss, the system has the capability of opening a fluid supply valve to provide make up fluid and increase system pressure.

RELATED APPLICATIONS

This continuation application claims the benefit of national stage entryU.S. patent application Ser. No. 15/757,519 filed on Mar. 5, 2018. U.S.application Ser. No. 15/757,519 in turn claims priority to PCTapplication PCT/US17/65829 filed on Dec. 12, 2017. The PCT applicationin turn claims priority to two U.S. Provisional Patent Applicationshaving the same inventor as the present application: namely, applicationnumber 62434762 filed on Dec. 15, 2016 and having the title “Device andmethodology for early detection of fluid loss and notification andsystem shutdown for a closed loop fluid heat transfer system”; andapplication No. 62/554,259 filed on Sep. 5, 2017 having the same titleas the previous provisional application. All the related applicationsare incorporated herein by reference in their entireties.

BACKGROUND

Serious damage can result to homes or structures that incorporate aliquid heat transfer system should the system be breached, either by aslow leakage loss over a long period of time, or by a suddencatastrophic breach of the system. Typical hydronic systems incorporatea boiler feed valve with a backflow preventer, to replace normal watervolume losses, which has a component caused by air coming out ofsolution and being removed by an air separator. A bladder type expansiontank modulates volume due to temperature changes, to maintain systempressure within a narrow range, and will only accommodate very minoractual loss of water volume. The feed valve adds water if and when thesystem falls below the normal operating set pressure. It is common tooperate the system with this feed valve supplied at all times by theincoming water supply line, so that make-up water can be added as calledfor.

A very slow leak that develops anywhere in the system may cause acontinual water loss less than the rate of fill, and thus may continuefor an extended period of time, resulting in possibly hidden andpossibly severe water or mold damage before the leak is discovered, eventhough the heating system may continue to provide heat as usual. Asudden catastrophic breach may result in a very large amount of waterbeing released before discovery, particularly if the structure is notoccupied at the time the breach occurs. If the feed valve is able tosupply water at a rate at least equal to the rate of water loss, thesystem will continue to operate, but at greatly diminished heat outputand all the while discharging large volumes of water into the structure.With heating disabled, the structure may fall below freezing temperatureinside, leading to further damage to the heating and or plumbingsystems.

It is a practice of some heating equipment installers to operate a newlyfilled system for a certain period of time, to remove the bulk of theair in solution, and then close the incoming water supply to the feedvalve. This has the effect of limiting possible water release to theamount of water contained within the system, assuming any breach is atthe lowest point, or to the amount of water released to bring systempressure to either zero, or to the point of activating a low watercutoff or a low pressure shut-off, either of which may be incorporatedin the heating appliance. In a typical medium size residence, the volumeloss to reduce pressure to that of static head may be as little as 16fluid ounces.

This approach of isolating the system prevents catastrophic water damageto the structure, but a very slow leak may reduce system pressure to thepoint that the circulator pump will cavitate due to insufficientpressure to maintain fluid on the suction side. At that point, it islikely that the pump will burn out due to running dry because of anunsatisfied call for heat. The safety shutoffs on the appliance may ormay not come into play, and the likely first warning of a problem is adrop in temperature in the structure, with no readily observable cause.A structure space temperature monitoring system may only be activatedafter there is a circulator pump failure, necessitating replacement ofnow failed equipment, which can be problematic during nights andholidays.

Water sensor monitoring systems well known in the prior art have thelimitation that they will only detect fluid loss at the location of thesensor. The most damaging leaks in hydronic systems occur at locationsremote from the appliances, usually within wall or floor assemblies, andare not initially readily observed until there is a significant waterloss and or consequent damage. Water flow monitoring systems areemployed as whole-house domestic water system leak detectors. Thesesystems cannot adequately protect the hydronic heating system in anoccupied structure. The allowable flow levels must of necessity be fargreater than the smallest potential leaks in the hydronic system. If aflow-monitoring detector is dedicated to the hydronic system, thatsystem must be continuously open to supply pressure, in order to detecta flow condition. The detector must then decide if flow is excessive,and actively close off the supply water. Very low leakage rates may bebelow the sensitivity of such detectors, or less than the allowablevolume for a given time period.

If a hydronic system is closed off from the supply water source, it ispossible for leakage to disable the circulator pump without any flowbeing indicated by the detector. A hydronic system requires only aminimum pressure to maintain function. Monitoring flow into the systemmust therefore infer a pressure condition in order to decide whatprotective actions to undertake. Heating systems may equally easilydevelop a leak in both occupied and unoccupied structures, whether inheating mode or during seasonal shutdown, so that a leak detector andsafety shutdown must perform equally well under all these circumstances.

Infrared imaging cameras may be successfully used to locate leaks in ahot water heating system, which may occur within floor or wallassemblies, and are thus not readily observable. In typical tradepractice, this method will only be employed after the likelihood of aleak has been established, which may come well after the initiation of avery slow and damaging leak into the structure.

An existing device has the primary purpose of a complete separation ofthe hydronic system from the domestic water supply. Make-up fluid isstored in a tank, and added to the hydronic system by a pump, which iscontrolled by a pressure switch. This allows for the use of fluids otherthan water. Leakage is measured indirectly, via an alarm signal when thestorage tank is depleted. There may not be any notification of a veryslow leak in the hydronic system until long after initiation, which mayresult in considerable hidden damage.

Another existing device monitors pressure in an isolated hydronicsystem, and in the most basic configuration, merely reports a drop inpressure to a preset warning level. It is the responsibility of thewarning recipient to take an explicit action to add fluid to the system.An enhancement includes the ability to actively open a supply valve torestore pressure. This version will only warn of presumed leakage if therestore function happens too frequently in a given time period, and mayallow for feeding of a very slow leak indefinitely, with consequenthidden damage as the result.

The increase in use of hot water radiant heating systems has resulted inan increase in a particularly insidious type of leak and subsequentwater damage. These systems incorporate a large amount of water filledtubing directly under the subfloor, or even the flooring materialitself. It is very easy to penetrate the tubing with a misplacedfastener, either during construction or after occupancy. Pneumaticstaples and finish nails and drywall screws are the most likelyculprits, and any may penetrate one wall or both sides of the tube. Thepenetration may be sealed by the tubing material sufficiently to holdpressure during a pressure test normally performed during theconstruction phase of the project.

A fastener may also penetrate and be sealed by the tubing after thesystem is filled and running, when a much lower operating pressure is inthe system than during testing. In either case, the water in the heatingsystem will start a slow process of corroding the fastener and or thealuminum layer of a Pex-AL-Pex tube. At some point, typically a numberof months after start-up, water pressure will force its way around thedegraded fastener, and a leak ensues.

BRIEF SUMMARY OF THE DRAWINGS

FIG. 1 is a graph of parameters pertaining to embodiments of a leakdetection system as plotted against system pressure, and a graph ofsystem pressure against time for various circumstances of pressure lossin closed loop fluid heat transfer system.

FIG. 2 is a schematic representation of a closed loop fluid heattransfer system including a leak detection system according to a firstsystem embodiment of the present invention.

FIG. 3 is a schematic representation of a closed loop fluid heattransfer system including a leak detection system according to avariation of a first system embodiment of the present invention.

FIG. 4 is a flowchart for a first method of operation of a leakdetection system for a closed loop fluid heat transfer system accordingto a first system embodiment of the present invention.

FIG. 5 is a flowchart for a variation of a method of operation of a leakdetection system for a closed loop fluid heat transfer system accordingto a first system embodiment of the present invention.

FIG. 6 is a flowchart for a second method of operation of a leakdetection system for a closed loop fluid heat transfer system accordingto a first system embodiment of the present invention.

FIG. 7 is a schematic representation of a closed loop fluid heattransfer system including a leak detection system according to a secondsystem embodiment of the present invention.

FIG. 8 is a schematic representation of a closed loop fluid heattransfer system including a leak detection system according to a firstembodiment of the present invention, with the addition of a domesticwater shutoff and pressure monitoring system according to a third systemembodiment of the present invention.

FIG. 9 is a flowchart for a method of operation of a domestic watershutoff and pressure monitoring system according to a third systemembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Overview

Embodiments of the invention comprise a device and method of use thatwill maintain normal system operating pressure while also reliablydetecting even very small fluid losses in any closed loop fluid heattransfer system that incorporates a pressure regulated means ofsupplying make-up fluid, and also an air separator and air vent and aproperly sized bladder type expansion tank. Make-up fluid is typicallyintroduced into said hydronic systems at a point on the system pipingbetween said expansion tank and said air separator, at what is termedthe “point of no pressure change”.

When the circulator pump is operating, fluid flow generates a dynamicpressure, which is offset by a loss of static pressure. Resistance toflow steadily reduces this dynamic pressure in the piping system, as thefluid flows through the piping loop. A pressure regulated fluid supplyentering the system where flow can occur would constantly be trying tocompensate for dynamic pressure changes, resulting in overfilling andthen fluid release through the pressure relief valve.

The point of no pressure change is a vital concept, as it allows foraccurate filling and maintenance of system pressure under all conditionsof operation. The bladder type expansion tank typically has a pre-chargeair pressure that is equal to or slightly less than the desired systemfill pressure. The fill pressure must always be greater than the statichead pressure of the system, in order to maintain pressure on thesuction side of the circulator pump under all conditions.

After filling the system the air is purged from the fluid, and fluidtopped up to operating pressure as necessary. Typically these systemsare filled cold, so that even idle at room temperature, the containedfluid expands slightly, and expands more so as operating temperatureincreases. This thermal expansion is accommodated by the fluid pushinginto the bladder of the expansion tank, with a corresponding slightincrease in system pressure due to the compression of the containedpre-charge air on the opposite side of the bladder.

If the system is now isolated from the source, such that the feed valveis dis-allowed from adding fluid, pressure at the point of “no pressurechange” can vary only due to change in volume due to thermal expansionand contraction, loss of volume due to extraction of entrained air, orloss of fluid mass due to leakage of any type. This is illustratedconceptually in FIG. 1. Thermal expansion and contraction by itself willtypically result in measured pressure modulating in a range above theinitial fill pressure, and presents no issues. Extraction of air is avery slow process, which becomes slower over time, and results in a verysmall change in volume. This volume loss may eventually be so slight asto only need compensating for after a period of months, or even a year.

In a typical residential system, normal operating pressure may bereduced below system minimum pressure with the loss of as little as onepint of fluid. If the fluid volume is reduced by any cause, the pressurewill drop slightly until all of the initial fluid volume in the bladderis evacuated. Any further volume loss will result in a nearinstantaneous drop in pressure, first to that of the static head of thesystem, and then the pressure will fall further depending on how muchfluid loss and draining down of the system may occur.

Systems depicted each show a system comprised of a hot water applianceand associated system components, and imply the presence of distributiontubing, such as underfloor radiant tubing, but the scope of thisinvention is not limited to such examples. In the example drawings, therelative positions of the air separator, air vent, expansion tank, feedvalve, system shutoff valve and pressure transducers or switches, withrespect to each other in the vertical plane, may be construed as thetrue relationship in the vertical plane in an actual hydronicinstallation although the actual vertical distances or ratios of thevertical distances between these various components may be different inthe actual hydronic system.

Said physical relationships may allow for the extraction and release oftrapped air from the system as a whole, and may also prevent disruptiveair accumulation at said expansion tank and said pressure transducers orswitches. As illustrated in the example drawings, the piping betweensaid elements typically embody no reverse traps or negative slopes.Other physical relationships are contemplated, that differ from therelationship of the various system components shown, and thatsubstantially prevent and minimize the entrapment of air within thesystem piping between any of the system shutoff valve, the expansiontank and the air separator.

The method of use of an embodiment of this invention is to allow thefeed valve to fill said system to a set pressure value, above theminimum pressure to maintain normal functioning, and then close saidsystem off from said fluid supply source. A pressure transducer withsufficient sensitivity may generate a signal proportional to actualpressure of said system, which may then be utilized to indicate actualloss of fluid volume in said system.

Embodiments of the invention incorporate a power actuated normallyclosed system shutoff valve in the piping connecting said fluid sourceto said hydronic system. Said valve thus isolates said hydronic systemand allows or dis-allows the possible addition of fluid into said systemthrough said feed valve. With said system shutoff valve closed, fluidmay only be lost from said system, and system pressure will respond tovolume change due to fluid or volume loss of any causation.

Embodiments of the invention may open said system shutoff valve only fora limited duration, and only after a time delay, in response to a presetfalling pressure, and only if associated with a moderate and tolerableloss of fluid volume. Opening of said system shutoff valve may allowsaid feed valve to restore system pressure and maintain normal systemoperation. A further loss of pressure, to below the established systemminimum operating pressure, is indicative of a serious and probablyongoing loss of volume. If at any time such a reduced pressure level maybe detected, said controller may disable the system shutoff valve and asystem circulator pump, and possibly also the appliance, to preventpossible equipment failure. Said controller may also issue warningnotifications of any type, as will be described.

A second method of use may be to open said system shutoff valve atcalendar or timed intervals for only a short duration, thus allowingsaid feed valve to compensate if and as necessary, for small volumelosses of any expected cause such as extraction of dissolved air. Thisinvention may allow for said system to become self-regulating as regardsfluid volume, but at all times said system and the surrounding structureis protected from unrestrained fluid loss emanating from any part orlocation of entire said hydronic system. Leakage is deduced by means ofmonitoring system pressure, and not by discovery of actual leaked fluid,which leakage may occur anywhere in the system piping, fittings andcomponents.

Hydronic systems typically employ a feed valve that is allowed todirectly and immediately respond to any changes to actual systempressure relative to a single setpoint. Embodiments of this inventionrely on measuring and then regulating system pressure as a stepfunction. It is unnecessary to continuously log pressure data in orderfor the invention to function as intended.

Pre-programmed time intervals may be employed as a notch filter, andlook forward from a realized point of intermediate but not directlydisabling pressure loss. Said controller then is able to separatecritical events from ordinary and necessary system pressure maintenance.In said second method, the action of maintaining system pressure isdis-associated from the response to potentially damaging pressure loss,in order to preclude feeding any system leakage.

Definitions

The terms and phrases as indicated in quotes (“ ”) in this section areintended to have the meaning ascribed to them in this Terminologysection applied to them throughout this document including the claimsunless clearly indicated otherwise in context. Further, as applicable,the stated definitions are to apply, regardless of the word or phrase'scase, to the singular and plural variations of the defined word orphrase.

The term “or” as used in this specification and the appended claims isnot meant to be exclusive rather the term is inclusive meaning “eitheror both”.

References in the specification to “one embodiment”, “an embodiment”, “apreferred embodiment”, “an alternative embodiment” and similar phrasesmean that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least an embodimentof the invention. The appearances of the phrase “in one embodiment” invarious places in the specification are not necessarily all meant torefer to the same embodiment.

The term “couple” or “coupled” as used in this specification and theappended claims refers to either an indirect or direct connectionbetween the identified elements, components or objects. Often the mannerof the coupling will be related specifically to the manner in which thetwo coupled elements interact.

Directional and/or relationary terms such as, but not limited to, left,right, nadir, apex, top, bottom, upper, lower, vertical, horizontal,back, front and lateral are relative to each other and are dependent onthe specific orientation of an applicable element or article, and areused accordingly to aid in the description of the various embodimentsand are not necessarily intended to be construed as limiting.

In this description, “system” shall refer to the totality of thephysical components and piping of a hydronic heat transfer system as istypically installed.

The “appliance” is the source or equipment, such as a hot water boileror heat pump that heats and or cools the fluid, for distribution to thepoint of use.

In this description, “domestic system” shall refer to the totality ofthe physical components and piping of a domestic water supply system asis typically installed, exclusive of the components of said hydronicheating system.

In this description, “controller” shall refer to the totality of thephysical components, which receive system inputs, analyze said inputs,and respond with actions or signals as has been programmed or installed.Said controller can consist of, but is not limited to, any of aprogrammable logic controller, a dedicated microprocessor, analog todigital input-output device, mechanical or electromechanical timingdevices, and associated power supplies, displays, switches, relays andindicator lights. Said controller can also incorporate any type of wiredor wireless Internet connectivity, or wireless connectivity to any typeof mobile device.

The description refers frequently to the components commonly found inresidential hydronic heating systems, but this should not be construedas limiting the application of this device to only such systems.

Terminology

System Parameters, Setpoints and Programmable Values may be as follows:

-   A) Pa Actual System Pressure    -   Pa is the actual system pressure, as measured at the previously        described point of no pressure change, at any given moment in        time.-   B) Pmax Maximum Normal System Operating Pressure    -   Pmax is the greatest pressure value encountered during normal        system operation, which allows for variations due to thermal        expansion and contraction of the fluid volume, as mediated by        the bladder type expansion tank. Said tank may be sized to        prevent Pmax from exceeding the set value of a pressure relief        valve as is typically installed in hydronic systems, thus        preventing unintended loss of fluid from said system.-   C) Pl Lowest Normal System Operating Pressure    -   Pl is the lowest pressure value encountered during normal system        operation, which allows for variations due to thermal expansion        and contraction of the fluid volume, as mediated by the bladder        type expansion tank.-   D) Pm Minimum System Operating Pressure    -   Pm is the minimum operating pressure at which all components of        said system will continue to operate and transfer heat as        designed, without mechanical failure due to adverse conditions.        Pm can be established as the greater of the minimum operating        pressure of the appliance, or, of the sum of the static head        pressure of the system plus the minimum pressure required to        prevent cavitation at the circulator pump or pumps. Static head        pressure for water systems may be roughly calculated as one half        the total system piping height in feet, expressed as pounds per        square inch, and typically a residential hydronic system        requires about 5 psi additional to ensure that the circulator        pump may operate properly without cavitation. Once established,        this value for Pm may be entered into the controller as an        operating parameter.-   E) Pn Normal System Operating Pressure (Third Pressure Set Point)    -   Pn is the normal operating pressure of the system, which can be        physically realized by the manual adjustment of the feed valve.        Said pressure can be a differential above the minimum operating        pressure such that one or more distinct alarm condition        setpoints may be reached as the system pressure falls, while        maintaining a deadband between each setpoint that will usually        exceed twice the sensitivity of the pressure sensor or of the        feed valve pressure regulator mechanism. In an embodiment of the        invention, Pn may be entered into the controller as an operating        parameter.-   F) Pw Pressure at First Warning Notification (First Pressure Set    Point)    -   Pw is the Pa reached on falling system pressure at which the        controller will typically send a first notification and or        enable an alarm as shall be described below. This value is less        than Pl and greater than Ps by typically an increment greater        than twice the sensitivity of the pressure transducer, such that        a deadband will exist between Pw and Ps. Pw may be established        and programmed into the controller during setup of the system.-   G) Ps System Shutdown Pressure (Second Pressure Set Point)    -   Ps is the Pa reached on falling system pressure at which said        controller will typically send a second notification and/or        enable an alarm as shall be described below and in some        embodiments may also de-energize one or more system components        as shall be described below, and may also lock out the        energizing of said system shutoff valve (Fluid supply valve) to        limit further fluid loss. De-energizing system components will        protect the structure from continued fluid loss, and protect the        appliance and or the circulator pump(s) from mechanical damage        due to running dry. If said controller of a particular        embodiment has the ability to communicate via the Internet,        persons or entities at remote locations may be apprised of the        system shutdown. Warning of a heating system shutdown is        typically provided earlier in embodiments of the present        invention than would be in a system utilizing a prior art        structure space temperature sensing device, which would likely        not provide an alert until after system components had failed.        Ps can be established as the Pa less than the Pm by an increment        greater than the sensitivity of the pressure sensor, such that a        deadband will exist between Pm and Ps, thus allowing the system        to operate at the established Pm. Ps is typically established        and programmed into the controller during the startup of the        system.-   H) Pr Alarm Reset Pressure    -   Pr is the Pa reached on rising pressure that may cancel previous        notifications and/or safety shutdown commands, and may also send        a notification to that effect by any means as shall be described        below. Pr may be established as the Pa greater than Pw and also        less than Pn usually by an increment greater than the        sensitivity of the pressure sensor or of the feed valve, such        that there is a deadband between Pr and Pn, and may be        programmed into the controller during system startup.-   I) T_(L1) First Time Interval for Lockout of Shutoff Valve Actuation    (First Predetermined Period of Time)    -   T_(L1) is a time parameter used in an embodiment of this        invention. T_(L1) is the set duration of time between starting        and ending a first consecutive timing function of said        controller, commencing when Pa falls to Pw. T_(L1) may be an        embodied value in said controller, or may be programmed and or        altered specific to a given system. Initiation of said first        timing function may preclude any subsequent re-initiation of        said first timing function until the conclusion of a third        consecutive timing function of duration T_(L2).-   J) Do Time Duration For Energizing of the System Shutoff Valve    (Second Predetermined Period of Time)    -   Do is a time parameter used in an embodiment of this invention.        Do is the set duration of time between starting and ending a        second consecutive timing function of said controller,        commencing at the end of T_(L1). Do is the duration of time        during which the system shutoff valve may be energized, but is        also subject to any other constraints or limitations of        operation. Do may be established during system setup by        measuring the minimum time required to raise Pa from Ps to Pn        (also referred to herein as “fill time”), under normal incoming        fluid supply pressure, and adding a time increment in order to        achieve full possible pressure Pn while also allowing for        variations in system conditions. Do may be programmed into said        controller during system setup. Do will enable said feed valve        to compensate for the worst allowable pressure loss that may        occur during normal operating conditions but also limits        catastrophic fluid loss to only this short time period, which is        typically in the range of 30 to 300 seconds. In an embodiment of        the invention, Do is the maximum amount of time that said system        shutoff valve may remain energized, regardless of the value of        Pa.-   K) T_(L2) Second Time Interval for Lockout of System Shutoff Valve    Actuation (Third Predetermined Period of Time)    -   T_(L2) is a time parameter used in an embodiment of this        invention. T_(L2) is the set duration of time between starting        and ending a third consecutive timing function of said        controller, commencing at the conclusion of Do. T_(L2) may be an        embodied value in said controller, or may be programmed and or        altered specific to a given system. At the conclusion of T_(L2),        said first timing function may be allowed to re-initiate.-   L) Is Time Interval Between Open Intervals of System Shutoff Valve    -   The controller may be configured such that Is may be the time        interval from one initiation of the opening of said system        shutoff valve to the next initiation of the opening of said        system shutoff valve, or may be configured as the interval from        the timed closing of said system shutoff valve to the next        succeeding opening of said system shutoff valve. Is may be        established and programmed into said controller during system        setup. Is may be no greater than the maximum time interval that        will allow Pa to stay greater than Pw, while the system is under        normal operating conditions and subject to no aberrant fluid or        pressure losses. In a typical operating residential heating        system that has had the bulk of the dissolved air purged out,        this would likely be at least several days, and may likely be        programmable for a period of ten days or more. In a variation,        interval Is may be embodied as a calendar based function, such        that said system will open said system shutoff open valve at        programmed calendar intervals.

Example Calculations and Determination of Values

The following examples of programmable values and the derivation thereofare intended to be exemplary for a typical residential hydronic heatingsystem and should not be construed as limiting.

-   -   Establish system minimum pressure: [(½×system piping height in        feet)+5] psi    -   Verify appliance minimum pressure, for example: 10 psi    -   Calculate minimum system pressure, for example:    -   For a typical 2 story house: [½×15 (feet)+5] psi=12.5 psi=Pm    -   Ps may be set slightly below Pm, such as 12.3 psi    -   For a single story house: [½×6 (feet)+5] psi=8 psi; must use        Pm=10 psi In this example, it may be preferable to set Ps        slightly above Pm, in order to insure system pressure will be        maintained above any low pressure limit switch embodied in the        appliance.    -   Verify transducer sensitivity, for example: 0-30 psi at 1%        accuracy    -   Determine and verify expansion tank pre-charge pressure:    -   Pre-charge may be less than Ps by at least 1.5 times transducer        sensitivity, so that system setpoints are always in the range of        measurable pressure.    -   For this example [12.3−(1.5×0.3)] psi=pre-charge pressure; use        11.8 psi    -   Determine setpoints:    -   For this example, (2×0.3) psi plus (0.1) psi may be used as the        minimum differential between Ps and Pw and also between Pw and        Pn.    -   For the Ps=12.3 psi, Pw may be set at 13.0 psi or above; it may        be preferred to use 13.3 psi as a setpoint, to indicate a        greater (but still very small) change of fluid volume. With Pw        set at 13.3 psi, Pn may similarly be determined to be 14.3 psi,        and enabled by a physical setting of the feed valve, or as a        programmed setpoint in the controller. Pr may be set at 14.0        psi, to insure a reset even if Pn does not restore to exactly        full value.

Establish Do=(elapsed time for feed valve to raise Pa from Ps to Pn(fill time))×(Multiplier>1)

-   -   For example system: (150 seconds measured)×(1.5)=225 seconds=Do    -   Establish T_(L1) and T_(L2):    -   T_(L1) is reflective of what may be arbitrarily be determined to        constitute a rapid or catastrophic leak. Guidance may come by        creating a small drip through a system draindown valve, and        measuring the elapsed time for Pa to fall from Pn to Ps. In a        noticeable leak, this will usually be only a matter of minutes.        It may be advisable to also measure the quantity of water        released, as this will essentially be a constant that may be        correlated with timed events to assist in identifying a possible        cause of leakage. It is preferable to set T_(L1) a minimum of        five times Do, and typically not less than 15 minutes. Setting        T_(L1) at one hour will typically identify a rapid or        catastrophic leak, and may consistently allow an initial system        refill when the actual rate of leakage is as yet unknown.    -   T_(L2) is reflective of what may be arbitrarily be determined to        constitute a slow or very slow leak. In an intact system, it is        possible to operate for an entire heating season without adding        any fluid. A corroding fastener that penetrates radiant tubing        may typically take several days to initially release a        significant volume of water. A typical setting of T_(L2) of 5 to        10 days will identify a slow, or possibly accelerating, rate of        leakage that may definitely be attributed to some breach of the        system. If Pa falls from Pn to Ps during T_(L2), a slow leak is        identified. If Pa falls from Pn to Pw during T_(L2), a very slow        leak is identified. This may be indicative of a component        condition, such as a valve stem leak, or a leaking fitting. At        initial system startup, and for a period of a week to a month        thereafter, air extraction may be a greater factor. It may be        preferred, during this time period, to set T_(L2) to a much        lower value, typically 1 to 3 days, to allow adding make-up        water as necessary.

System Elements

A first system embodiment of the invention may consist of the followingelements as described herein and illustrated schematically in FIG. 2. Anelectrically operated normally closed system shutoff valve 202 may beinstalled in the fill piping 110 between a fluid source 100 and ahydronic system, for the purpose of allowing or dis-allowing make-upfluid flow through the feed valve 116. In a typical residential heatingsystem, said make-up fluid fill piping 110 can connect to said hydronicsystem between an expansion tank 120 and an air separator 112.

Typically fluid is drawn from appliance 102 via a system supply pipe 104through said air separator 112 by the circulator pump 118. Fluid ispushed away around one or more distribution loops and re-enters saidappliance 102 through a return pipe 106. Typically said valve 202 can beself-closing on loss of power, and can be capable of holding against apressure differential greater than the maximum incoming supply fluidpressure.

Said shutoff valve 202 can communicate with a controller 302, byhard-wired connection or by wireless connection, such as, but notlimited to Bluetooth. Power to operate said shutoff valve 202 may besupplied by said controller 302, or may be drawn directly from thestructure power grid 300. A pressure transducer 204 that generates asignal proportional to hydronic system pressure may be installed in saidpiping between said expansion tank 120 and said air separator 112, whichis the point of no pressure change during operation of said circulatorpump 118 of said system.

Said transducer 204 may be combined in a manifold 206 with said systemshutoff valve 202, and may also include a mechanical pressure gauge or agauge port. The proximal installation of a manual boiler drain valve 122may assist in the setup and adjustment of the pressure values, byfacilitating fluid release while simultaneously observing said systempressure. It may be preferred to oversize said expansion tank 120 aboveminimum system requirements, as this may result in a greater change influid volume for a given change in pressure, and thus make it possiblefor the installed detector to more accurately control said systempressure.

In the example drawings, the relative position in the vertical plane ofsaid air separator 112, air vent 114, expansion tank 120, feed valve116, shutoff valve 202, and pressure transducer 204, may be construed asthe true relationship in the vertical plane in an actual installation.This physical relationship, embodying no traps or reverse slopingpiping, may allow for the release of trapped air from the system as awhole, and also prevent air accumulation at the pressure transducer 204and or gauge, which may otherwise affect actuation. Said pressuretransducer 204 may communicate with said controller 302 by hard wireconnection or by wireless connection such as, but not limited toBluetooth. If the pressure transducer 204 communicates with thecontroller 302 wirelessly, power to operate this transducer may be by acontained battery, or drawn directly from the structure power grid 300,which may incorporate a battery backup.

A microprocessor-based controller 302 may be located separately from ormay be unitized in a manifold assembly 222 with said valve 202 andtransducer 204. Said controller 302 may incorporate a digital display ora monitor screen 316, which may incorporate a touch screen or mayutilize any type of touch pad or buttons, to which together provide forentering system parameters and for the monitoring of system status andfunctioning.

Said controller 302 may have the capability to communicate wirelessly304 by cellular phone service directly to a mobile device 306. Saidcontroller 302 may have the capability to communicate with a local areanetwork by any means. This means of communication may be, but is notlimited to, a hard-wired connection 308 such as Ethernet or USB, or maybe wirelessly 304 by Bluetooth, 802.11 Wi-Fi, or any other system.Wireless communication may be utilized only to communicate with saidshutoff valve 202 and said pressure transducer 204, or said controller302 may communicate with a wireless router 310 that communicates with alocal computer 312 or directly with any device that may connect to theInternet 314. Said controller 302 may thusly be programmed and ormonitored by said local computer 312 or by any device with an Internetconnection.

Said controller 302 may be powered by the structure power grid 300, andmay incorporate a battery backup power supply, or may be powered by anintegral battery. The controller 302 may monitor said battery and mayissue a notification prior to depletion of the battery. Said controller302 may have an input 320 for the signal from said pressure transducer204, which may be hard-wired or wireless. Said controller 302 may havean output 328 for operation of said system shutoff valve 202, which maybe hard-wired or wireless. If said output 328 is hard-wired, saidcontroller 302 may output a control signal for a power relay that canactivate a power circuit for said system shutoff valve 202, or saidcontroller 302 may output the required power to operate said systemshutoff valve 202 directly. If said controller 302 communicates withsaid system shutoff valve 202 wirelessly, the signal received at thevalve location may activate a power relay at said location.

The simplest embodiment of this invention may use hard-wired connectionsbetween components, with the controller 302 supplying power for theactuation of said system shutoff valve 202, as in a typical residentialheating system all components will be located in close proximity to eachother in a single building space, thus allowing for short interconnectsand visual contact between all components.

Said controller 302 may embody an output 336 for a first notification offalling system pressure, which notification 336 may be the closing ofone or more pairs of dry contacts, which may enable the functioning of alocal alarm and or enable a first notification via any type of installedhome security or monitoring system. Said output 336 for said firstnotification may simultaneously or exclusively be a power output thatmay activate a local alarm annunciator, which may be either visual orauditory. Said output 336 for said first notification may be exclusivelyor simultaneously a wireless signal via Bluetooth, 802.11 Wi-Fi, or anyother system, to a LAN router 310, and then to a local computer 312,which may embody an Internet connection 314. Said first notification maybe directed to or available to any device with an Internet connection.

Said controller 302 may embody an output 338 for a second notificationof additional loss of system pressure. Said output 338 for said secondnotification may simultaneously or exclusively be a power output thatmay activate a local alarm annunciator, which may be either visual orauditory. Said output 338 for said second notification may beexclusively or simultaneously a wireless signal via Bluetooth, 802.11Wi-Fi, or any other system, to a LAN router 310, and then to a localcomputer 312, which may embody an Internet connection 314.

Said output 338 for said second notification may simultaneously orexclusively supply actuation power to normally closed output relay 344and or normally closed output relay 346. Actuation of said relay 344 mayinterrupt the low voltage control circuit 360 and de-energize a powerrelay 124 of said pump 118, or may directly interrupt the power supplycircuit of said pump 118. Actuation of said relay 346 may interrupt thelow voltage control circuit 362 of said appliance 102, or may directlyor indirectly interrupt the appropriate power circuit. Certain boilersknown to the art have an integral freeze protection system for theboiler itself, which allows heat output at pressures as low as 2 or 3psi. Said units may not typically be de-energized by the described leakdetection and safety shutdown invention, as this may dis-enable the lowpressure freeze protection capability.

A second variation of said first system embodiment may eliminate thepermanent connection to a domestic water supply. The source of make-upfluid for a hydronic system may be a discrete pressurized make-up fluidcontainment vessel, and may not be restricted as to type of fluidemployed. Said vessel can be a bladder type expansion tank, and cantypically be pre-charged to a pressure above Pmax of said hydronicsystem, such that fluid contained within said vessel can be introducedinto said hydronic system by the action of said pre-charge pressureacting on said bladder. A pressure regulating valve on the dischargepiping of said vessel may be set to a desired value of Pn.

Said vessel can utilize a closure valve and hose connection, for thepurpose of filling or re-filling said vessel, up to the pressure limitof said vessel or the capability of the fill source employed. Saidvessel may incorporate a pressure gauge for visual monitoring ofavailable make-up fluid, or said vessel may incorporate a pressuretransducer or pressure switch on the fluid side of said bladder. Whensaid contained fluid pressure falls to a setpoint at or above Pmax, aninput signal to said controller may cause a third notification to beissued by any embodied means. Said storage vessel may incorporate ableed valve at the high point of the discharge piping of said vessel toallow for purging of air during or after filling said vessel.

A third variation of said first system embodiment may also eliminate thepermanent connection to a domestic water supply. The source of make-upfluid for the hydronic system may be a fluid supply tank, which may beopen to atmospheric pressure and may have no restriction on type offluid employed. Said tank may be manually filled or re-filled asnecessary. Said fluid can be transferred into said hydronic system bymeans of an electrically operated pump which may be enabled by saidcontroller during interval Do, in lieu of said system shutoff valve. Apressure regulating valve on the discharge of said pump may be set to adesired value of Pn. A check valve may be embodied in the pipingsucceeding said pump.

A fourth variation of said first system embodiment may consist of thefollowing elements as described herein and illustrated schematically inFIG. 3. Said previously disclosed pressure transducer 204 may besupplanted by two pressure switches 208 and 210, which may be installedin the piping between said expansion tank 120 and said air separator112. Said pressure switches 208 and 210 may be combined in a manifold206 with said system shutoff valve 202, and may also include amechanical pressure gauge 212 or a gauge port. A controller 396 maydispense with the analog to digital converter function typicallyassociated with a previously disclosed pressure transducer 204.

Said first pressure switch 208 may be adjusted and set to close a pairof contacts when system pressure Pa falls to a level Pw. The closing ofsaid pressure switch 208 may complete a controller input circuit 322,and enable the sending of a first notification by any means and or closea normally open relay output 336 which may send a first notification toan installed home security system or a monitoring service for same. Saidsecond pressure switch 210 can be adjusted and set to close a pair ofcontacts when system pressure Pa falls to a level Ps. The closing ofsaid pressure switch 210 may complete a controller input circuit 324,and enable the sending of a second notification by any means. Theclosing of said pressure switch 210 may close a normally open relayoutput 338, which may send a second notification to an installed homesecurity system or a monitoring service for same.

Concurrently said closing of said pressure switch 210 may disable output328 to said system supply valve 202, so that said valve 202 willself-close and or be prevented from opening. Concurrently said closingof said pressure switch 210 may enable a normally closed relay 344 tointerrupt a control circuit 360 in order to de-energize a power relay124 of said circulator pump 110. Concurrently said closing of saidpressure switch 210 may enable a normally closed relay 346 to interruptan appliance control circuit 362 in order to de-energize said systemappliance 102. A plurality of functions may be enabled by an embodimentof said controller 396, or may be enabled by a plurality of externalrelays that are each energized by the closing of said relay outputs 336or 338.

Method of Operation

A first method of operation of a first system embodiment of thisinvention is as described herein and illustrated conceptually by FIG. 1and represented as a flowchart in FIG. 4. Element numbers of shapes foroperational steps shown in FIG. 4 are indicated herein in parentheses.Values Ps, Pw, Pn and Pr may be calculated for or assigned to a specificsystem, and programmed (400) in said controller 302. Values of T_(L1),Do and T_(L2) may be embodied in said controller 302, or may bedetermined and programmed by an installer of a specific system. Saidexpansion tank 120 pre-charge pressure may be set and verified as lessthan Ps. Said heat transfer system may be tested and filled (402) tosystem pressure Pn, and said controller 302 may be tested for properoperation. Said hydronic system and controller 302 may then be madeoperational (404).

During normal operation of said system, Pa will range from a lowpressure of Pl up to some greater pressure Pmax, resulting from thethermal expansion and contraction of the fluid (406), and may be limitedby a pressure relief valve that may be incorporated into said system toprevent damage from over-pressurization. Unless energized by saidcontroller 302, said normally closed system shutoff valve 202 may at alltimes deny the addition of fluid by the feed valve 116. Said fluidvolume may be reduced by the extraction of trapped or dissolved air insaid system. Said fluid volume may also be reduced at any time by lossof fluid mass, which is to say, system leakage of any kind or cause(408).

The analog signal from pressure transducer 204 at input 320 may becontinuously sampled (404) and processed by an analog to digitalconverter embodied in said controller 302. A digital value of Pa maythen be compared to said programmed values Pw and Ps. As long as Pa isgreater than Pw (410), said controller 302 may take no action. When Pais reduced to Pw or less (412), a first notification (414) may be sentby any means (480) as previously described and/or close a normally openrelay output 336 which may send a first notification (482) to aninstalled home security system or a monitoring service for same.

A series of three consecutive timing functions may simultaneously beinitiated. A first timer is initiated (434), counts up to T_(L1) (436),ends (438), and then starts (440) a second timer. Said second timercounts up to Do (442), ends (444), and then starts (446) a third timer.Said third timer counts up to T_(L2) (448) and then ends (450). At saidstart (434) of said first timer a timing cycle (432) enablement registeris started. At said end (450) of said third timer, a timing cycle (432)enablement register is canceled. For the duration of said timing cycle(432), said controller 302 may block (430) the re-initiation of saidtiming cycle.

Said system shutoff valve 202 may be energized open (460) at the startof said second timer (440). Said system shutoff valve 202 may bede-energized closed (464) at the end of said second timer (444). Saidopening (460) of said system shutoff valve 202 for duration Do may allowsaid system feed valve 116 to add fluid (462) as required to raise Pa toPn, presuming no ongoing fluid losses. De-energizing (464) said systemshutoff valve 202 at the conclusion of Do may deny any continued fillaction (466) should said feed valve 116 be unable to restore Pa to Pndue to ongoing fluid loss.

If Pa increases to Pr or above (468), said first notification may becanceled (470) and relay output 336 may be opened (472). A suddenincrease in rate of fluid loss during Do may prevent Pa from reachingeither Pr or Pn, but as energizing of said system shutoff valve 202 istime limited, potential discharge of fluid through any breach isconsequently limited as well (466). If at any time Pa falls to Ps orless (416), said controller 302 may issue a second notification (418) byany means (484) as previously described and or close a normally openoutput relay 338, which may send a second notification (486) to aninstalled home security system or a monitoring service for same.

Said controller 302 may simultaneously (420) block (494) output 328 andtherefore end or prevent the energizing (496) of said system shutoffvalve 202, insuring isolation (498) of said hydronic system from saidfluid source 100. Said controller 302 may simultaneously (420) open anormally closed output relay 344, to interrupt (490) a control circuitor a power circuit for said circulator pump 118. Said controller 302 maysimultaneously (420) open a normally closed output relay 346, tointerrupt (492) a control or power circuit for said system appliance102. By disabling said pump 118 or appliance 102, possible damage to anyof said equipment due to operation at less than Pm is thus prevented.

Said controller 302 may not have any means of automatically restoringsystem pressure after said second notification, and may require a manualreset (488) of said second notifications. Said system may be re-startedafter inspection, repair and the manual filling and purging (402) ofsaid system to pressure Pn.

A loss of grid power (422) may temporarily produce the same results asdoes system shutdown (420), by de-energizing said circulator pump 118,appliance 102, and system shutoff valve 202, thereby denying feeding ofany leak or breach of said system. A restoration of power may allow saidcontroller 302 to resume (404) said pressure monitoring function andtake any actions as may be indicated by said detected pressure value.

The volume of fluid associated with a change in Pa from Pn to Pw andalso from Pw to Ps may be essentially constant, such that the programmedvalues of T_(L1) and T_(L2) may create a time frame for such volumelosses, and hence be an indicator of the rate of change of said systempressure, without the need for recording Pa. A rapid or catastrophicleak may be discovered should Pa fall to Ps within T_(L1) of said firsttimer.

Presuming that Pa may be restored to Pn during Do of said second timer,a slow leak may be discovered should Pa fall to Ps or less within T_(L2)of said third timer, and a very slow leak may be discovered should Pafall to Pw or less, but remain above Ps, within T_(L2) of said thirdtimer. In such a case, said timing cycle (430) and consequent possibleaddition of fluid may be allowed to be repeated. Presuming that Pa maybe restored to Pn during Do of said second timer, and should Pa remainabove Pw for T_(L2) of said third timer, said system may be monitoredfor subsequent or repeated loss of pressure to Pw. Monitoring may be byembodied data logging by said controller 302, or by an alarm monitoringservice, or by manually recording instances of said first notification.

If Pa should fall to Pw only two or three times per year, it may bepresumed that said hydronic system is intact and fully functioning asintended. Said controller 302 may be made more sensitive to rate of lossby increasing the values of T_(L1) and or T_(L2). Said controller 302may be made less sensitive to rate of loss by decreasing the values ofT_(L1) and or T_(L2). Less sensitivity may be necessary or desirable inthe case of an older system, which may be subject to unavoidable buttolerable fluid losses due to such causes as a failing pump seal orvalve stem packing. In said case, T_(L1) and or T_(L2) may be adjustedover time, to allow fluid to be added with greater frequency withoutinvoking system shutdown. A change in the frequency of Pa falling to Pwmay indicate a change in circumstance of fluid loss, and may indicatethe advisability of investigation. If system leakage is indicated, saidleakage may then be searched for visually, or by means of an infraredcamera device or by any other means, before serious hidden water damagemay occur to the structure.

A second variation of said first method embodiment is described hereinand represented by a flowchart in FIG. 5. Element numbers of shapes foroperational steps shown in FIG. 5 are indicated herein in parentheses.Said operational steps conform to said first variation methodology, withan additional steps as herein described. Said controller 302 maycontinuously sample system pressure Pa, and may de-energize (464) output328 during interval Do, to allow said system shutoff valve 202 to closewhen Pa equals or exceeds Pn (576).

Said system shutoff valve 202 may be of a type with rapid response time,which may typically be a fraction of a second, and may also be of a lowCv, or coefficient of flow. If said valve 202 is selected so as to beable to reliably limit Pn without consequential pressure overshoot, saidfeed valve 116 typically associated with a hydronic system may beeliminated. Do (442) may remain as a time limitation for said systemshutoff valve 202 to possibly be open, for the purpose of preventinglimitless water release under any circumstance.

In a third variation of said first method embodiment, said controller302 can be programmed with a system start-up cycle, which may embodysaid first methodology, but may utilize reduced or fractional values ofT_(L1) and T_(L2) as has been programmed for normal system operation.Said reduced values can be manually selected, set by programmedcalculation relative to said input values, or set to default values bysaid program logic. At system initiation or at the manual reset andre-starting of said hydronic system after a system shutdown, saidcontroller 302 may run said system methodology for a programmed durationof time, that may typically be seven to thirty days, at said reducedvalues of T_(L1) and T_(L2). Said duration may be manually programmed ormay be embodied in said controller, and may automatically switch to saidfull values of T_(L1) and T_(L2) at the conclusion of said start-upcycle. Said start-up cycle has the effect of allowing more frequentadditions of fluid to said system during the initial period ofoperation, when there is a probability of greater volume loss due to airextraction.

In a fourth variation of said first method embodiment, said controller302 can be programmed with a periodic function test cycle for saidsystem shutoff valve 202, in order to regularly verify the ability ofsaid valve 202 to properly operate. Said test cycle may consist ofenergizing said system shutoff valve 202 open for a short interval, suchas, but not limited to, five to thirty seconds. The duration of saidinterval may be manually programmed or may be embodied in saidcontroller methodology.

Said test cycle may occur at repetitive calendar intervals, whichintervals may be a manually entered or at a pre-programmed value, suchas but not limited to, once per week or once per month. Said test cyclemay occur at repetitive time intervals, which intervals may be amanually entered or a pre-programmed value, such as but not limited to,every seven to thirty days. Said controller 302 may be programmed todeny any said individual test cycle should said test cycle occur during,or overlap with, T_(L1) or T_(L2). Said system shutoff valve 202 may beconfigured with an end switch, and may be enabled to report each actualsuccessful opening of said valve 202 during said test cycle.

In a fifth variation of said first method embodiment, said controller302 may not incorporate any or all direct physical control functions ordisplays 316. Initial set-up and operation of said controller 302 andsaid associated programming of values may be by action of an ancillarydevice such as a computer 312 connected directly or through a LAN 310,or by a mobile device 306 connected to said controller 302 through a LAN310, or directly connected wirelessly 304 by Bluetooth, 802.11 Wi-Fi, orany other means. Said controller 302 may be distributed with, or withaccess to, a software application for said computer 312 or mobile device306. Said application may have any of the following attributes:

-   -   Setpoints may be by user-defined values, or the application may        require the installer to enter raw data concerning the hydronic        system, and said application may then calculate and install the        setpoints in the microprocessor memory of said controller.        Examples of data that may be required may be appliance 102 model        number and serial number, specified minimum operating pressure        of the appliance 102, height of hydronic piping system, and the        measured elapsed time for said feed valve 116 to raise Pa from        Ps to Pn.    -   Operating setpoints such as Pw and Ps may have embedded values        relative to input data, or may be configurable by the installer,        or alterable by the installer within programmed parameters.    -   Initiation can require the successful completion of a        verification test cycle that may include, but is not limited to,        raising Pa from Ps to Pn during time interval Do, and manually        releasing fluid from said hydronic system so as to test        transmittal of said first notification at Pw and test        transmittal of said second notification at Ps.    -   Said application may receive data from said controller 302        continuously, and or may download data as and when connected to        said ancillary or mobile device 306.    -   Said application may display any available output or setpoint        from said controller 302, including, but not limited to, said        system setpoints, pressure Pa, duration of Pa less than Pw, and        enabled operation of said system shutoff valve 202 as reported        by said previously described end switch.    -   Said application may store initialization data and or said        verification test result data. Said stored data may be required        as supporting documentation for any warranty or liability claim        action initiated by the installer and or the end user.    -   Said application may send any, or all, available data to a        third-party server.    -   Said application may be configured to allow firmware updates via        Internet connection, either automatically or by user permission.

A second method embodiment of the invention may be as described hereinand represented as a flowchart in FIG. 6. Element numbers of shapes foroperational steps shown in FIG. 6 are indicated herein in parentheses.Values Ps, Pw, Pn and Pr may be calculated for or assigned to a specificsystem, and programmed (600) in said controller 302. The values of Isand Do may be determined and programmed (600) by an installer for aspecific system, or either may be embodied in the programming of saidcontroller 302. Is may typically be of three to fifteen days duration.Said expansion tank 120 pre-charge pressure may be set and verified asless than Ps. Said hydronic system may be tested and filled (602) tosystem pressure Pn, and said controller 302 may be tested for properoperation. Said hydronic system and controller 302 may then be madeoperational (604).

During normal system operation, Pa will range from a low pressure of Plup to some greater maximum pressure value, resulting from the thermalexpansion and contraction of the fluid (606). A pressure relief valvemay be incorporated into said system to prevent damage fromover-pressurization. Unless energized by said controller 302, saidnormally closed system shutoff valve 202 may deny the addition of fluidby the feed valve 116. Said fluid volume may be reduced by theextraction of trapped or dissolved air in said system. Said fluid volumemay also be reduced by loss of fluid mass, which is to say, systemleakage of any kind or cause (608).

Upon startup, said controller 302 may start a periodic first timer(634), count up to Is (636), and then end (638). At each and every timerend (638), the timer count may clear to zero and re-start said timer(634). At the conclusion of each and every interval Is, a second timermay start (640), count up to Do (642), and then end (644). Said systemshutoff valve 202 may be energized open (660) for duration Do (642) ofsaid second timer. Said system shutoff valve 202 may be de-energizedclosed (664) at the end of said second timer (644). Said opening (660)of said system shutoff valve 202 may allow said system feed valve 116 toadd fluid (662) if and as necessary to raise Pa to Pn (610), presumingno ongoing fluid losses. A sudden increase in rate of fluid loss duringDo may prevent Pa from reaching either Pr or Pn, but as energizing ofsaid system shutoff valve 202 is time limited, potential discharge offluid through any breach is consequently limited as well (666).

An analog signal from pressure transducer 204 at input 320 may becontinuously sampled (604) and processed by an analog to digitalconverter embodied in said controller 302. The digital value of Pa maythen be compared to said programmed values Pw and Ps. As long as Pa isgreater than Pw, said controller 302 may take no action. When Pa isreduced to Pw or less (612), a first notification (614) may be sent aspreviously described (680) and or output relay 336 may be closed toactivate (682) a local alarm or home security monitoring system. If,during scheduled time period Do, Pa increases to Pr or above (668), saidfirst notification may be canceled (670) and relay 336 may be opened(672) to cancel said local alarm.

If at any time Pa falls to Ps or less (616), said controller 302 mayissue a second notification (618) as previously described (684) and orclose output relay 338 to activate (686) a local alarm or home securitymonitoring system. Said controller 302 may simultaneously (620) block(694) output 328 and end or prevent the energizing (696) of said systemshutoff 202, insuring isolation (698) of said hydronic system from saidfluid source 100. Said controller 302 may simultaneously open (620) anoutput relay 344, to interrupt (690) a control circuit 360 or a powercircuit for said circulator pump 118. Said controller 302 maysimultaneously open (620) an output relay 346, to interrupt (692) acontrol circuit 362 or power circuit for said system appliance 102. Bydisabling said pump 118 or appliance 102, possible damage to any of saidequipment due to operation at less than Pm is thus prevented.

Said controller 302 may not have any means of automatically restoringsystem pressure after said second notification, and may require a manualreset (680) of said second notification. Said system may be re-startedafter inspection, repair and the manual filling and purging (602) ofsaid system to pressure Pn. A loss of grid power (622) may temporarilyproduce the same results as does system shutdown (620), by de-energizingsaid circulator pump 118, appliance 102, and system shutoff valve 202,thereby denying feeding of any leak or breach of said system. Arestoration of power may allow said controller 302 to resume saidpressure monitoring function (604) and take any actions as may beindicated by said detected pressure value.

In a second variation of said second method embodiment said controller302 may continuously sample system pressure Pa, and may de-energize saidoutput 328 to close said system shutoff valve 202 during interval Do,when Pa equals or exceeds Pn. Said system shutoff valve 202 may be of atype with rapid response time, which may typically be a fraction of asecond, and may also be of a low Cv, or coefficient of flow. If saidvalve is selected so as to enable said controller 302 to reliably limitPn without consequential pressure overshoot, said feed valve 116typically associated with a hydronic system may be eliminated. Do mayremain as a time limitation for said system shutoff valve 202 topossibly be open, for the purpose of preventing limitless water releaseunder any circumstance.

In a third variation of said second method embodiment, said controller302 may be programmed with a system start-up cycle, which may embodysaid second method, but may utilize a reduced or fractional value of Isas has been programmed for normal system operation. Said reduced valuemay typically be, but is not limited to, one to three days. Said reducedvalue may be manually selected, set by programmed calculation relativeto said input value, or set to a default value by said program logic.

At system initiation or at a manual reset and re-starting of saidhydronic system after a system shutdown, said controller 302 may runsaid system methodology for a programmed duration of time, that maytypically be seven to thirty days, at said reduced value of Is. Saidduration may be manually programmed or may be embodied in saidcontroller, and may automatically switch to said full value of Is at theconclusion of said start-up cycle. Said start-up cycle has the effect ofallowing more frequent additions of fluid to said system during theinitial period of operation, when there is a probability of greatervolume loss due to air extraction.

In a fourth variation of said second method embodiment, said firstnotification may not activate an alarm and or an alarm monitoringentity. Said first notification may be transmitted by any embodiedmeans, and may be manually recorded by the recipient. Said firstnotification may be an entry in a data logging memory, which may betransmitted or made available to recipients as directed. If Pa equals orexceeds Pr, said controller (302) may take equivalent actions to notifyas described.

In a fifth variation of said second method embodiment, said controller302 may not incorporate any or all direct physical control functions ordisplays 316. Initial set-up and operation of said controller 302 andsaid associated programming of values may be by action of an ancillarydevice such as a computer 312 connected directly or through a LAN 310,or by a mobile device 306 connected to said controller 302 through a LAN310, or directly connected wirelessly 304 by Bluetooth, 802.11 Wi-Fi, orany other means. Said controller 302 may be distributed with, or withaccess to, a software application for said computer 312 or mobile device306. Said application may have any of the following attributes:

-   -   Setpoints may be by user-defined values, or the application may        require the installer to enter raw data concerning the hydronic        system, and said application may then calculate and install the        setpoints in the microprocessor memory of said controller.        Examples of data that may be required may be appliance 102 model        number and serial number, specified minimum operating pressure        of the appliance 102, height of hydronic piping system and the        measured elapsed time for said feed valve 116 to raise Pa from        Ps to Pn.    -   Operating setpoints such as Pw, Ps and Pn may have embedded        values relative to input data, or may be configurable by the        installer, or alterable by the installer within programmed        parameters.    -   Initiation can require the successful completion of a        verification test cycle that may include, but is not limited to,        raising Pa from Ps to Pn during time interval Do, and manually        releasing fluid from said hydronic system so as to test        transmittal of said first notification at Pw and test        transmittal of said second notification at Ps.    -   Said application may receive data from said controller 302        continuously, and or may download data as and when connected to        said ancillary or mobile device 306.    -   Said application may display any available output or setpoint        from said controller 302, including, but not limited to, said        system setpoints, pressure Pa, duration of Pa less than Pw, and        enabled operation of said system shutoff valve 202 as reported        by said end switch.    -   Said application may store initialization data and or said        verification test result data. Said stored data may be required        as supporting documentation for any warranty or liability claim        action initiated by the installer and or the end user.    -   Said application may send any, or all, available data to a        third-party server.    -   Said application may be configured to allow firmware updates via        Internet connection, either automatically or by user permission.

System Elements for a Second System Embodiment

A second system embodiment may consist of the following elements asdescribed herein and illustrated schematically in FIG. 7. Anelectro-mechanical timer or electronic timer 380 may be powered by gridpower 300 or by a battery source. Said timer 380 may be, but is notlimited to, a seven-day timing cycle. It may be preferred to embody aminimum “on” time of no more than one to five minutes. A normally closedrelay 348 may interrupt a timer output 328 circuit that may otherwiseenergize said system shutoff valve 202. A manifold assembly 222, similarto that previously disclosed for a fourth variation of said first systemembodiment, may embody a manifold 206, a system shutoff valve 202, apressure gauge 212, and two pressure switches 208 and 210.

A normally open pressure switch 208 may close at a pre-set fallingpressure Pw, and re-open at a pre-set rising pressure Pr. Said switch208 may enable or disable a relay control circuit. Said relay controlcircuit may be powered by a source 392 which may be, but is not limitedto, 120 volt AC grid power, or 24 volt AC. Said switch 208 may enable alocal alarm 384, and or energize a normally open relay 386 to send afirst notification to an installed home security system or to amonitoring service for same. Closing said switch 208 may also send aninput to an Internet connected device 382. Said device 382 may send afirst notification over said Internet by any means, which may be, but isnot limited to, cellular phone service or wired or wireless connectivityto a LAN.

A normally open pressure switch 210 may close at a pre-set fallingpressure Ps, and re-open at a pre-set rising pressure Pr. Said switch210 may enable or disable a relay control circuit. Said relay controlcircuit may be powered by a source 392 which may be, but is not limitedto, 120 volt AC grid power, or 24 volt AC. Said switch 210 may enable alocal alarm 388, and or energize a normally open relay 390 to send asecond notification to an installed home security system or to amonitoring service for same. Closing said switch 210 may also input toan Internet connected device 382. Said device 382 may send a secondnotification over said Internet by any means, which may be, but is notlimited to, cellular phone service or wired or wireless connectivity toa LAN.

Said switch 210 may enable a normally closed relay 348, which mayinterrupt said output 328 of said timer 380, and cause said valve 202 toclose or be prevented from opening. Said switch 210 may enable anormally closed relay 344, which may interrupt a low voltage controlcircuit 360 to open a power relay 124 and disable said circulator pump118. Said switch 210 may enable a normally closed relay 346, which mayinterrupt a low voltage control circuit 362 to disable said appliance102.

Method of Operation

A method of operation of said second system embodiment may be avariation of said previously disclosed second method of operation. Saidtimer 380 may be set or programmed for one or more “on” intervals ofduration Do. Said value of Do may be determined as previously disclosed.Typically, said timer 380 may embody a seven-day timing cycle, typicallywith one “on” interval per cycle. Said system shutoff valve 202 may beenergized open for duration Do of said timer. Said periodic opening ofsaid system shutoff valve 202 may allow said system feed valve 116 toadd fluid if and as necessary to raise Pa to Pn, presuming no ongoingsystem fluid losses. A sudden increase in rate of fluid loss during Domay prevent Pa from reaching either Pr or Pn, but as energizing of saidsystem shutoff valve 202 is time limited, potential discharge of fluidthrough any breach is consequently limited as well.

If Pa is reduced to Pw or less, said switch 208 closes, and closes saidrelay 386 and or activates said local alarm 384. A first notificationmay be sent by said device 382, by any means as previously described.If, during scheduled time period Do, Pa increases to Pr or above, saidalarm 384 and said relay 386 may be de-energized, and cancellation ofsaid first notification may be sent by said device 382.

If at any time Pa is reduced to Ps or less, said switch 210 closes, andactivates said alarm 388 and or said relay 390. Said relay 348 may beenergized open, to interrupt said output 328 and prevent energizing ofsaid valve 202. Said relay 344 may be energized to disable saidcirculator pump 118, and said relay 346 may be energized to disable saidappliance 102. A second notification may be sent by device 382, by meansas previously described. System shutdown may preclude any opening ofsaid valve 202, so that said system may require a manual re-start afterinspection, repair and the manual filling and purging of said system topressure Pn.

System Elements for a Third System Embodiment

A third embodiment may include all elements of a first embodiment andmay further consist of the additional following elements as describedherein and illustrated schematically in FIG. 8. An electrically operateddomestic supply valve 252 may succeed a connection to said hydronicsystem fill piping 110, and may provide for the isolation of theremainder of the installed domestic water system from the incoming watersupply 100. Said domestic supply valve 252 may be capable of holdingagainst a pressure differential greater than the full incoming watersupply pressure 100.

Said domestic supply valve 252 can be self-closing on loss of power,thus limiting possible fluid loss in case of a grid power outage, butmay allow for a manual override to allow domestic water use during apower outage. Said domestic supply valve 252 may be separate from or bephysically embodied with said leak detector system shutoff valve 202, inany of said embodiments of said leak detector system.

A bladder type expansion tank 256 that can be rated for potable wateruse can be installed in the branch piping that supplies the domestic hotwater heating appliance 258. If said domestic supply valve 252 should beclosed, said expansion tank 256 may allow for thermal expansion orcontraction of the water in the domestic plumbing system, and therebyprecludes the necessity of simultaneously shutting off the domestic hotwater heating appliance 258.

A pressure transducer 254 may be installed downstream of said domesticsupply valve 252. Said domestic pressure transducer 254 may communicatewith a controller 398 by a hard wire connection 326 or by a wirelessconnection such as, but not limited to Bluetooth. If said pressuretransducer 254 communicates with said controller 302 wirelessly, powerto operate said transducer 254 may be by a contained battery, or drawndirectly from the structure power grid 300, which may incorporate abattery backup.

A variation may utilize a pressure switch in lieu of said transducer254. Said normally open pressure switch may close on a preset fallingpressure, and re-open on a pre-set rising pressure.

Said controller 398 may include all elements of a first embodiment andmay further consist of the following additional input, outputs, andfunctions. An output 334 may be enabled to energize said domesticshutoff valve 252. An input 326 may receive an analog signal from saiddomestic pressure transducer 254. A relay output 342 may enable a fourthnotification if actual domestic system pressure falls below a programmedsetpoint. Said relay 342 may activate a local alarm and or may send afourth notification to an installed home security system or to amonitoring service for same. Said controller 398 may be connected to aninstalled home alarm or security system by any wired or wireless means.Said controller 398 may be connected to a LAN router 310 by any wired308 or wireless 304 means and or directly connect to a mobile device306. Said controller 398 may by any previously described means receivean input signal for an UNOCCUPIED condition, and for an OCCUPIEDcondition.

A method of operation of said third system embodiment may be any of saidpreviously disclosed first or second methods of operation, and otherfunctions as described herein and represented as a flowchart in FIG. 9.Element numbers of shapes for operational steps in FIG. 9 are indicatedherein in parentheses. Said controller 398 may be programmed and linked(900) to an installed alarm system or mobile device.

A signal (902,904) to said controller 398 may cause an activation of anOCCUPIED mode (906) and may energize output 334 to cause said domesticsupply valve to open (908) and allow normal domestic water use (910). Aloss of power (920) may cause said domestic supply valve 252 to close(922), but said valve 252 may provide for a manual override (924) toallow domestic water use during a power outage.

A signal (930,932) to said controller 398 may cause activation of anUNOCCUPIED mode (934) and may de-energize said output 334 and may causesaid domestic supply valve 252 to close (936). Said closing of saiddomestic supply valve 252 may limit any source or cause of domesticsystem water loss to be no more than that which is statically containedwithin said domestic plumbing system. Said function may have thegreatest utility at such times as the structure is unattended for longperiods, such as seasonal non-use, or vacation periods during theheating season.

During said UNOCCUPIED periods, said controller 398 may continuouslysample domestic system pressure (938). Said controller 398 may embody aclock and calendar function (950), and may embody a data log (952) ofdomestic system pressure values, which may be reported by any embodiedmeans of communication (954). Should the pressure in said domesticsystem fall (940) to a programmed value (942) below the lowest possiblesupply pressure and also above the maximum static head pressure of saiddomestic system, said controller 398 may enable an output 342 to issue afourth notification (944). Said fourth notification may simultaneouslyor exclusively be sent to a home alarm system and or to a LAN and ordirectly to a mobile device. Said fourth notification may indicate asignificant loss of pressure in said domestic system during any periodwhile in UNOCCUPIED mode. This indicator may be relied on prior tosignaling an OCCUPIED mode (960).

VARIATIONS AND OTHER EMBODIMENTS

The various embodiments and variations thereof, illustrated in theaccompanying Figures and/or described above, are merely exemplary andare not meant to limit the scope of the invention. It is to beappreciated that numerous other variations of the invention have beencontemplated, as would be obvious to one of ordinary skill in the art,given the benefit of this disclosure. All variations of the inventionthat read upon appended claims are intended and contemplated to bewithin the scope of the invention.

A variation of any of the preceding embodiments may be to control theelectrically operated system shutoff valve either locally or remotely,after said first notification has been sent, by conscious action ofeither the local occupant or a remote monitoring service. A furthervariation may be to employ a manually operated system shutoff valve,which may be actuated manually after said first notification, by eitherthe occupant or a system service provider. This variation may beutilized for any system not directly connected to a pressurized fluidsource, such as, but not limited to, glycol or glycol-water mixes. Thisvariation may dispense with said feed valve and or backflow preventer,as the fill pressure may then be manually controlled.

Another variation may be to send device input data to a remotemonitoring service for the purpose of monitoring, recording and actingupon the received inputs; thereby obviating the need for locallyinstalled control logic. Such a variation may also compile data frommany systems, and thus be able to learn typical system performance, andthereby be able to better assess causes of system pressure losses. Afurther variation may be to employ individual electro-mechanical timedelay relays to effect intervals T_(L1), Do and T_(L2), in lieu ofprogrammed electronic timing functions embedded in microprocessormemory.

I claim:
 1. A method of detecting a leak in a hydronic heating orcooling system, the method comprising: providing the hydronic heating orcooling system, the hydronic heating or cooling system being a closedloop and including, one or more pressure sensors, the one or moresensors configured to sense when a system pressure drops below or risesabove at least first, second, and third pressure set points, the firstpressure set point being greater than the second pressure set point andthe third pressure set point being greater than the first pressure setpoint, a circulator pump, a controller, the controller including a timerand being configured to control operations of the hydronic heating orcooling system responsive to pressure changes indicated by the one ormore pressure sensors; a system shutoff valve coupled to a fluid supply,an expansion tank, at least one of a heating appliance and coolingappliance, an air separator including an air vent, piping fluidlycoupling at least the circulator pump, the system shutoff valve, the airseparator, the expansion tank, the one or more pressure sensors, and theheating or cooling appliance, and a fluid contained in the hydronicheating or cooling system; at system initiation, measuring a fill timeby opening the system shutoff valve to record the elapsed time to raisethe system fluid pressure from the second pressure set point to thethird pressure set point; periodically sampling system pressure atregular intervals; initiating a leak determination cycle when the systempressure drops below the first pressure set point, the leakdetermination cycle performing in order, (1) starting the timer to counta first predetermined period of time and preventing an opening of thesystem shutoff valve during the first predetermined period of time, thefirst predetermined period of time being greater than the fill time, (2)at the conclusion of the first predetermined period of time, startingthe timer to count a second predetermined period of time, the secondpredetermined period of time being greater than the fill time and lessthan twice the fill time, (3) during the second predetermined period oftime, opening the system shutoff valve when the system fluid pressure isgreater than the second pressure set point and below the third pressureset point, (4) closing the-shutoff valve no later than a conclusion ofthe second predetermined period of time, (5) at the conclusion of thesecond predetermined period of time, starting the timer for a thirdpredetermined period of time, preventing the opening of the systemshutoff valve during the third predetermined period of time, andproviding a first notification when the system fluid pressure dropsbelow the first pressure set point, the third predetermined period oftime being greater than the first predetermined period of time, and (6)providing a second notification when the system pressure drops below thesecond pressure set point.
 2. The method of claim 1, further comprising:turning off the circulator pump when the system pressure drops below thesecond pressure set point.
 3. The method of claim 2, wherein said firstand second notifications comprise one or more of the following: a visualalarm; an audible alarm; an automated telephone call; a text message; anemail; and an electronic notification sent to a predetermined device. 4.The method of claim 1, further comprising preventing opening of thesystem shutoff valve when system pressure drops below the secondpressure set point.
 5. The method of claim 1, wherein the controllercomprises a microprocessor.
 6. The method of claim 1, further comprisinglogging and storing data pertaining to the system initiation, the leakdetermination cycle, and the sampling of system pressure.
 7. The methodof claim 1, logging data when the system pressure drops to or below thefirst pressure set point.
 8. A method of detecting a leak in a hydronicheating or cooling system, the method comprising: providing the hydronicheating or cooling system, the hydronic heating or cooling system beinga closed loop and including, one or more pressure sensors, the one ormore sensors configured to sense when a system pressure drops below orrises above at least first, second, and third pressure set points, thefirst pressure set point being greater than the second pressure setpoint and the third pressure set point being greater than the firstpressure set point, a circulator pump, a controller, the controllerincluding a timer and being configured to control operations of thehydronic heating or cooling system responsive to pressure changesindicated by the one or more pressure sensors; a system shutoff valvecoupled to a fluid supply, an expansion tank, at least one of a heatingappliance and cooling appliance, an air separator including an air vent,piping fluidly coupling at least the circulator pump, the system shutoffvalve, the air separator, the expansion tank, the one or more pressuresensors, and the heating or cooling appliance, and a fluid contained inthe hydronic heating or cooling system; at system initiation, measuringa fill time by opening the system shutoff valve to record the elapsedtime to raise the system fluid pressure from the second pressure setpoint to the third pressure set point; periodically sampling systempressure at regular intervals; repeatedly and cyclically performing thefollowing operations in order, (1) starting the timer to count a firstpredetermined period of time and preventing an opening of the systemshutoff valve during the first predetermined period of time, (2) at theconclusion of the first predetermined period of time, starting the timerto count a second predetermined period of time, the second predeterminedperiod of time being greater than the fill time and less than twice thefill time, (3) during the second predetermined period of time, openingthe system shutoff valve when the system fluid pressure is greater thanthe second pressure set point and below the third pressure set point,(4) closing the-shutoff valve no later than a conclusion of the secondpredetermined period of time; providing a first notification when thesystem fluid pressure drops below the first pressure set point; andproviding a second notification when the system pressure drops below thesecond pressure set point and contemporaneously terminating performingoperations (1) through (4).
 9. The method of claim 8, furthercomprising: turning off the circulator pump when the system pressuredrops below the second pressure set point.
 10. The method of claim 8,wherein said first and second notifications comprise one or more of thefollowing: a visual alarm; an audible alarm; an automated telephonecall; a text message; an email; and an electronic notification sent to apredetermined device.
 11. The method of claim 8, further comprisingpreventing opening of the system shutoff valve when system pressuredrops below the second pressure set point.
 12. The method of claim 8,wherein the controller comprises a microprocessor.
 13. The method ofclaim 8, further comprising logging and storing data pertaining to thesystem initiation, the leak determination cycle, and the sampling ofsystem pressure.
 14. The method of claim 8, logging data when the systempressure drops to or below the first pressure set point.